Flow Passage Control Valve for Muffler

ABSTRACT

A flow passage control valve for a muffler may include an opening formed through a guide pipe, which forms an exhaust gas channel in the muffler, to form another exhaust gas channel, and a valve body adjusts an open amount of the opening by using a difference between an exhaust gas pressure exerted through the opening and a weight of the valve body.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Korean Application Serial Number 10-2008-0122517, filed on Dec. 4, 2008, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a muffler of a vehicle, particularly a flow passage control valve for a muffler that uses the gravity to change an exhaust gas flow passage inside the muffler.

2. Description of Related Art

Mufflers of vehicles in the related art have structures including a plurality of chambers that is formed by disposing one or more baffles in a muffler housing sealed to have a predetermined volume, an exhaust gas intake pipe that allows exhaust gas to flow inside the muffler housing, and an exhaust gas discharge pipe that allows the exhaust gas to flow outside from the muffler housing such that the exhaust gas that has flowed in the muffler housing through the exhaust gas intake pipe flows outside with the pressure and noise reduced from the mufflers through the exhaust gas discharge pipe while flowing through a predetermined flow channel formed inside the muffler housing.

FIG. 1 shows an example of a muffler according to the related art, in which an exhaust gas intake pipe 2 that allows exhaust gas discharged outside from the engine is connected to the front of a muffler housing 1, which has a substantially elliptical box shape, to be communicated with the inside of housing 1 and an exhaust gas discharge pipe 3 that allows the exhaust gas with the pressure and noise reduced while flowing through a predetermined channel inside the housing to flow outside the housing is connected to the rear portion of housing 1 to protrude outside.

Further, a plurality of baffles 4 a, 4 b are disposed in the longitudinal direction of the housing inside muffler housing 1 such that the inside of the housing is divided into a plurality of chambers, exhaust gas intake pipe 2 passes through first baffle 4 a at the front portion, and a guide pipe 5 that guides exhaust gas flowing inside through exhaust gas intake pipe 2 to exhaust gas discharge pipe 3 is disposed through second baffle 4 b at the rear portion.

Further, first baffle 4 a is equipped with a flow passage control valve 6 that opens/closes an exhaust gas flow channel in accordance with the driving velocity of the engine and flow passage control valve 6 opens when the engine is driven at a high speed, such that the flow of exhaust gas through the flow passage control valve is improved and the discharge pressure and noise are reduced, thereby improving the engine power.

Flow passage control valve 6 has a valve body 6 a that opens/closes a circular exhaust gas channel formed through first baffle 4 a and a support spring 6 b wound around a valve shaft of valve body 6 a to elastically support valve body 6 a.

When a spring type flow passage control vale having the above configuration in the related art is used, since the valve body is supported by the spring, the exhaust gas channel formed through the first baffle is opened in linear proportion to the exhaust gas pressure exerted in the valve body, in which the exhaust gas channel should be more opened to improve the engine power; however, the amount of opening of the variable valve is limited by the support force of the spring, which linearly increases, such that it is difficult to improve the engine power.

Further, the pulsation pressure of the exhaust gas is completely transmitted to the valve body of the flow passage control valve, such that the valve body opens the exhaust gas channel while continuously chattering or vibrating. Accordingly, it is difficult to accurately control the gas channel and it is required to use a special steel spring having high strength because the support spring that supports the valve body is exposed to the high-temperature exhaust gas, such that the cost of materials increases.

The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

BRIEF SUMMARY OF THE INVENTION

Various aspects of the present invention are directed to provide a flow passage control valve for a muffler that can improve the effect of noise reduction when the engine is driven at a low speed and improve the engine power when the engine is driven at a high speed by changing the exhaust gas channel, using the discharge pressure of exhaust gas and the gravity exerted against the discharge force.

In an aspect of the present invention, a flow passage control valve for a muffler may include an opening formed through a guide pipe, which forms an exhaust gas channel in the muffler, to form another exhaust gas channel, and a valve body may adjust an open amount of the opening by using a difference between an exhaust gas pressure exerted through the opening and a weight of the valve body, wherein at least a weight block that increase the weight of the valve body are additionally attached to the valve body.

The valve body may be pivotably connected to a valve housing, which is attached to the guide pipe, by a hinge shaft, wherein the valve body is formed in an arc shape and has one end pivotably connected to the hinge shaft, and the at least a weight block are fixedly attached to the other end of the valve body.

A closing-adjusting stopper that limits a closing stroke of the valve body when the valve body pivots in a direction of closing the opening may be provided in the valve housing.

An opening stopper that limits an opening stroke of the valve body when the valve body pivots in a direction of opening the opening may be provided in the valve housing and a stopper groove that selectively interacts with the opening stopper is formed at the valve housing.

In another aspect of the present invention, a flow passage control valve for a muffler, may include a muffler housing including a front chamber, a center chamber, and a rear chamber therein; an exhaust gas intake pipe passing through the first, center and rear chambers and fluid-connecting the first and rear chambers to receive an exhaust gas discharged from an engine; an exhaust gas discharge pipe passing through the center and rear chambers and fluid-connecting the center chamber and the outside to discharge the exhaust gas to the outside of the muffler housing; a guide pipe passing through the first, center and rear chambers and fluid-connecting the rear and front chambers, wherein the guide pipe includes an opening which is selectively opened to the center chamber by a valve body in accordance with a difference between an exhaust gas pressure exerted through the opening and a weight of the valve body.

The valve body may be formed in an arc shape corresponding to an outer circumference of the guide pipe.

The flow passage control valve may further include at least a weight block attached to the valve body to increase the weight of the valve body.

The valve body may include a flange formed in an arc shape corresponding to an outer circumference of the guide pipe to selectively cover the opening and one of the at least a weight block is fixed to one end portion of the flange and the other of the at least a weight block may be fixed to the other end portion of the flange, while the one end portion and the other end portion of the flange are aligned along a longitudinal direction of the guide pipe.

The valve body may be pivotably connected to a valve housing by a hinge shaft and the valve housing is fixed to the guide pipe.

A distance between the hinge shaft and the opening may be shorter than a distance between the hinge shaft and a weight center of the at least a weight block.

A closing-adjusting stopper that limits a closing stroke of the valve body when the valve body pivots in a direction of closing the opening may be provided in the valve housing, wherein the closing-adjusting stopper is disposed between the hinge shaft and the at least a weight block.

An opening stopper that limits an opening stroke of the valve body when the valve body pivots in a direction of opening the opening may be provided at one end portion of the valve body.

A stopper groove may be formed at the valve housing to selectively interact with the opening stopper.

The opening stopper may be disposed opposite to the closing-adjusting stopper with respect to the hinge shaft.

According to various aspect of the flow passage control valve of the present invention, since the cross-sectional area of the exhaust gas channel and the open amount of the valve are small when the engine is driven at a low speed, in which the influence of booming noise is large, the exhaust gas discharge noise is reduced and exhaust noise is effectively reduced. Further, when the engine is driven at a middle speed or a high speed, the cross-sectional area of the exhaust gas channel and the open amount of the valve increase in proportion to the driving speed of the engine and the engine power is effectively improved, such that it is possible to reduce the cost of materials because it is not required to mount a spring having large strength to support the valve, and accurately control the exhaust gas channel because less pulsation pressure of the exhaust gas is applied.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing the inside of a muffler equipped with a variable valve according to an exemplary embodiment of the related art.

FIG. 2 is a projected perspective view of a muffler equipped with a flow passage control valve according to an exemplary embodiment of the present invention.

FIGS. 3 to 5 are enlarged perspective views of the flow passage control valve according to an exemplary embodiment of the present invention.

FIGS. 6 and 7 are views illustrating the operation of the flow passage control valve according to an exemplary embodiment of the present invention.

FIGS. 8 and 9 are graphs comparing the flow passage control valve of an exemplary embodiment of the present invention with a flow passage control valve of the related art about engine speed to valve position.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

Referring to FIG. 2, the openings of both sides of a muffler housing 11 having a substantially elliptical box shape are covered by a front cap 12 a and a rear cap 12 b to seal the inside of the muffler housing 11. Two baffles 13 a, 13 b are disposed to be individually integrally fixed at a predetermined distance in the longitudinal direction of the muffler housing 11 inside the sealed space of the muffler housing, such that a front chamber 14 a, a center chamber 14 b, and a rear chamber 14 c are formed between front cap 12 a and the first baffle, between the first and second baffles, and between the second baffle and rear cap 12 b, respectively.

A plurality of holes 13 aa is formed through first baffle 13 a, such that front chamber 14 a and center chamber 14 b are communicated with each other by holes 13 aa.

An exhaust gas intake pipe 15 that allows exhaust gas discharged from the engine to flow inside the muffler housing 11 is inserted from the front portion of muffler housing 11 and sequentially passes through first and second baffles 13 a, 13 b to be communicated with rear chamber 14 c, and a plurality of holes 15 a is formed at the portion, which is positioned in front chamber 14 a, of exhaust gas intake pipe 15 such that exhaust gas intake pipe 15 is communicated with front chamber 14 a.

Further, an exhaust gas discharge pipe 16 that allows the exhaust gas to flow outside the muffler housing passes through second baffle 13 b and rear cap 12 b such that the exhaust gas in center chamber 14 b is discharged outside the muffler housing.

A guide pipe 17 passing through first and second baffles 13 a, 13 b to form an exhaust gas channel has both ends communicated with the front chamber and the rear chamber, respectively, and an opening 17 a that allows exhaust gas to flow into the center chamber is formed at the portion, which positioned in the center chamber, of the guide pipe, and the open amount of opening 17 a is adjusted by a flow passage control valve 18 according to an exemplary embodiment of the present invention.

Flow passage control valve 18, as shown in detail in FIGS. 3 to 5, has a valve housing 18 a attached on the outer circumference of guide pipe 17 and a valve body 18 c pivotably disposed in valve housing 18 a by a hinge shaft 18 b and formed in an arc shape to adjust the open amount of opening 17 a of guide pipe 17.

Further, valve body 18 c has flanges 18 ca, which axially extend, at the left and right edges and arc-shaped weight blocks 18 d are integrally fixed to flanges 18 a, such that the weight of valve body increases.

Further, a closing-adjusting stopper 18 e is mounted in the valve housing, such as a bolt, to adjust the closing stroke of valve body 18 c when valve body 18 c pivots by the weight in the direction of closing the opening, such that the closing motion of valve body 18 c is limited, when the lower end of valve body 18 c is placed on closing-adjusting stopper 18 e.

Further, an opening stopper 18 cd integrally protrudes from valve body 18 c to limit the opening stroke when valve body 18 c pivots upward in the direction of opening the opening by the exhaust gas pressure exerted through the opening and a stopper groove 18 aa where the opening stopper is inserted and locked is formed by cutting off the valve housing to the inside, such that the opening motion of the valve body is limited when opening stopper 18 cd is inserted and locked in stopper groove 18 aa.

Further, bushes 18 f are fitted on both ends of hinge shaft 18 b to reduce the operational noise, when valve body 18 c pivots around hinge shaft 18 b.

FIGS. 6 and 7 are side views illustrating the operational state of flow passage control valve 16 according to an exemplary embodiment of the present invention, in accordance with the driving speed of the engine. The flow passage control valve according to an exemplary embodiment of the present invention pivots downward by its own weight and the weight of the weight blocks unless external force applied such that valve body 18 c keeps closing opening 17 a of guide pipe 17.

Therefore, the exhaust gas that has flowed in the rear chamber flows into the front chamber through the guide pipe, thereafter flows into the center chamber through the holes of the first baffle, and then is discharged outside the muffler through the exhaust gas discharge pipe.

When the engine is driven at a low speed in the above configuration, the amount of exhaust gas discharged from the engine is small and a portion of the exhaust gas that has flowed in the muffler is applied to valve body 18 c as indicated by arrows, in which large moment is needed to open the opening 17 a by pivoting the valve body in the opening direction around hinge shaft 18 b as shown in FIG. 6.

That is, the exhaust gas pressure exerted in the valve body is positioned ahead of the center of weight of the entire valve body, such that the valve body is opened when more exhaust gas pressure is applied. However, since the exhaust gas pressure is low when the engine is driven at a low speed, the variable flow passage valve effectively reduce the booming noise when the engine is driven at a low speed by maintaining the position almost closing the opening of the guide pipe.

On the other hand, when the engine is driven at a high speed, as shown in FIG. 7, the pressure applied to the valve body by the exhaust gas gradually increases and the valve body pivots in the direction of opening the opening by the exhaust gas pressure, in which the point of action of the resultant force of the exhaust gas exerted in the valve body from the hinge shaft 18 b is substantially the same as the center of weight of the valve body, such that relatively small exhaust gas pressure is needed to maintain the open state of the valve body and the cross-sectional area of the exhaust gas channel increases while the opening amount of the opening that is opened by the valve body increases. Accordingly, a portion of exhaust gas flowing through the guide pipe directly flows inside the center chamber through the opening of the guide pipe and is then directly discharged outside the muffler through the exhaust discharge pipe. Therefore, the exhaust gas smoothly flows, such that the discharge pressure of the exhaust gas is reduced and the engine power is improved.

FIGS. 8 and 9 show graphs each comparing the opening torques to the valve positions and the valve positions to the driving speeds of the engine in a spring type variable flow passage valve of the related art and a gravity type variable flow passage valve of the present invention. In the variable flow passage valve of the related art, as the valve is opened, the support force of the spring that supports the valve body increases, such that large exhaust gas pressure that is in linear proportion to the open amount of the valve is needed, whereas exhaust gas pressure that is substantially in inverse proportion to the open amount of the valve is needed or the exhaust gas pressure does not substantially change in the present invention. Accordingly, as the driving speed of the engine increases, the open amount of the variable flow passage valve increases as compared with the related art, thereby improving the engine power.

For convenience in explanation and accurate definition in the appended claims, the terms “front” and “rear” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

1. A flow passage control valve for a muffler wherein an opening is formed through a guide pipe, which forms an exhaust gas channel in the muffler, to form another exhaust gas channel, and a valve body adjusts an open amount of the opening by using a difference between an exhaust gas pressure exerted through the opening and a weight of the valve body.
 2. The flow passage control valve as defined in claim 1, wherein at least a weight block that increase the weight of the valve body are additionally attached to the valve body.
 3. The flow passage control valve as defined in claim 2, wherein the valve body is pivotably connected to a valve housing, which is attached to the guide pipe, by a hinge shaft.
 4. The flow passage control valve as defined in claim 3, wherein the valve body is formed in an arc shape and has one end pivotably connected to the hinge shaft, and the at least a weight block are fixedly attached to the other end of the valve body.
 5. The flow passage control valve as defined in claim 4, wherein a closing-adjusting stopper that limits a closing stroke of the valve body when the valve body pivots in a direction of closing the opening is provided in the valve housing.
 6. The flow passage control valve as defined in claim 4, wherein an opening stopper that limits an opening stroke of the valve body when the valve body pivots in a direction of opening the opening is provided in the valve housing and a stopper groove that selectively interacts with the opening stopper is formed at the valve housing.
 7. A flow passage control valve for a muffler, comprising: a muffler housing including a front chamber, a center chamber, and a rear chamber therein; an exhaust gas intake pipe passing through the first, center and rear chambers and fluid-connecting the first and rear chambers to receive an exhaust gas discharged from an engine; an exhaust gas discharge pipe passing through the center and rear chambers and fluid-connecting the center chamber and the outside to discharge the exhaust gas to the outside of the muffler housing; a guide pipe passing through the first, center and rear chambers and fluid-connecting the rear and front chambers, wherein the guide pipe includes an opening which is selectively opened to the center chamber by a valve body in accordance with a difference between an exhaust gas pressure exerted through the opening and a weight of the valve body.
 8. The flow passage control valve as defined in claim 7, wherein the valve body is formed in an arc shape corresponding to an outer circumference of the guide pipe.
 9. The flow passage control valve as defined in claim 7, further including at least a weight block attached to the valve body to increase the weight of the valve body.
 10. The flow passage control valve as defined in claim 9, wherein the valve body includes a flange formed in an arc shape corresponding to an outer circumference of the guide pipe to selectively cover the opening and one of the at least a weight block is fixed to one end portion of the flange and the other of the at least a weight block is fixed to the other end portion of the flange, the one end portion and the other end portion of the flange being aligned along a longitudinal direction of the guide pipe.
 11. The flow passage control valve as defined in claim 7, wherein the valve body is pivotably connected to a valve housing by a hinge shaft and the valve housing is fixed to the guide pipe.
 12. The flow passage control valve as defined in claim 11, wherein a distance between the hinge shaft and the opening is shorter than a distance between the hinge shaft and a weight center of the at least a weight block.
 13. The flow passage control valve as defined in claim 11, wherein a closing-adjusting stopper that limits a closing stroke of the valve body when the valve body pivots in a direction of closing the opening is provided in the valve housing.
 14. The flow passage control valve as defined in claim 13, wherein the closing-adjusting stopper is disposed between the hinge shaft and the at least a weight block.
 15. The flow passage control valve as defined in claim 11, wherein an opening stopper that limits an opening stroke of the valve body when the valve body pivots in a direction of opening the opening is provided at one end portion of the valve body.
 16. The flow passage control valve as defined in claim 15, wherein a stopper groove is formed at the valve housing to selectively interact with the opening stopper.
 17. The flow passage control valve as defined in claim 15, wherein the opening stopper is disposed opposite to the closing-adjusting stopper with respect to the hinge shaft. 